Inside LightWave 3D v10: Lighting

This chapter explains how to light your models and scenes, including understanding basic lighting principles, using different light sources, enabling radiosity, lighting with gobos, creating soft shadows, and interacting with materials.

This chapter is from the book

This chapter is from the book

Working in 3D animation requires you to wear many hats. You're a draftsman, a 3D modeler, a producer, a painter, and even a gaffer—the person on a film set who takes care of the lighting. As a 3D animator, unless you're working in a big animation studio, you do your own lighting. And like many, you might consider lighting to be one of the less important aspects of your 3D animations, or simply an area that's outside your comfort zone. But lighting is crucial to your success as an animator, and fortunately it's not that hard to set up once you learn a few basic rules.

Lighting can be used for so much more than simply brightening a scene. Lighting can completely change the look of a shot. It can convey a mood, a feeling, or even a reaction. Lighting is vital in film, photography, and of course, 3D animation. Basic lighting can make your renders hot or cold; in other words, the color of the light you choose, where the lights are placed, and other aspects of lighting play a role in the final image. Lighting can improve your animations. But you need to be aware of some basic real-world principles before you can put it all together.

Lighting has an evil twin: texturing. OK, maybe it's not evil, but it can be challenging, and understanding texturing and how it's affected by lighting is one of your main goals as a 3D artist. This is probably one of the areas animators struggle with the most, and an area that can often make or break your project. However, don't worry; LightWave makes it easy to apply complex surfaces and get instant feedback. The look of a texture can change significantly based on the lighting associated with it. So, the two go hand in hand.

The previous chapter introduced you to LightWave 10's surfacing capabilities, including the Node Editor. Take that knowledge and move through this chapter to learn how to light your models and scenes.

This chapter instructs you on the following:

Understanding basic lighting principles

Using different light sources

Enabling radiosity

Lighting with gobos

Creating soft shadows

Interacting with materials

Working with Lights

Eight light types are available in LightWave Layout. Each has a specific purpose, but none is limited to that purpose. One thing to note is that each light has variances in settings. The area light, for example, can be scaled, but the spotlight can't. Distant lights use only rotation for their effect, whereas point lights use only position. Check out the Lighting Basics video on the book's DVD to see them in action.

NOTE

While you're working in LightWave's Modeler, you will not see a light source illuminating your shaded model in a Perspective viewport. Do not let that fool you, because it has nothing to do with your final lighting setup. Lights are available only in Layout.

Area lights. The best choice for creating true shadows, area lights create a brighter, more diffuse light than distant lights and therefore result in greater realism. They do, however, take longer to render than spotlights, distant lights, or point lights.

Distant lights. You can use a distant light for simulating bright sunlight, moonlight, or general lighting from a nonspecific source. Shadows from this light are hard. A distant light's position does not matter to your scene; only its rotation matters.

Dome lights. Used for creating a pseudo-environmental lighting environment, the dome light encompasses the entire scene.

Linear lights. You can use linear lights as elongated light sources, such as fluorescent bulbs and neon tubes. Linear lights can have realistic shadows but consume additional rendering time.

Photometric lights. Photometric lights have become more common in 3D applications over the last few years. This type of light uses a predetermined file called an IES file. You can find more about these file types at www.CGArena.com.

Point lights. You can use a point light to create sources of light that emit in all directions, such as a candle, lightbulb, or spark. Unlike a distant light, a point light's rotation does not matter in your scene; only its position matters. It, too, yields hard-edged shadows.

Spherical lights. Simliar to a point light, a spherical light might prove a better source of light for bulbs or special effects. Light is more concentrated to a sphere and less streaked than, say, a point light. The size of the light is important too; it affects the sharpness of the shadow. Smaller lights, sharper shadows. Larger lights, softer shadows.

Spotlights. The most commonly used lighting type, spotlights can be used for directional lighting, such as canister lighting, headlights on cars, studio simulation lighting, volumetric lighting, and more. Spotlight rotation and position play roles in your scene. A spotlight's shadows can be either hard or soft with shadow mapping.

The environment in which your animation lives is crucial to the animation itself, which is why we dedicate a chapter to lighting and textures. You should consider color, intensity, and ambient light each time you set up a scene. Too often, tutorials overlook the power of light, but you know better! Using lights, along with shadows, as elements in your animation can be as important as the models and motions you create. As you work through setting up lights in your 3D scenes, you should get used to setting one variable in particular: light intensity, also called brightness.

NOTE

Although we could dedicate this entire chapter and more to theory, design, and usage, we thought it better to demonstrate by doing. This chapter focuses specifically on using LightWave's lighting system so you can achieve results immediately. For an excellent lighting reference book, check out Digital Lighting & Rendering, second edition, by Jeremy Birn (New Riders, 2006).

As you work through lighting setups in this chapter and throughout this book, check out the types of lights LightWave has to offer. At the bottom of the LightWave Layout interface, you'll see the familiar item selection buttons—Objects, Bones, Lights, and Cameras. Click the Lights button, and then click the Properties button to the right. Alternatively, you can always press p to open any item's properties. You'll see the LightWave Light Properties panel (Figure 4.1).

Figure 4.1 The Light Properties panel, as shown with a single default light.

Looking closely at Figure 4.1, you can work your way down the panel, using the following explanations as your guide. At the very top of the panel, you can quickly clear all lights by clicking the Clear All Lights button. Be careful with this, as it clears all the lights in your scene, except for the default distant light. If you've changed the default light, clicking this option resets it. Next to the Clear All Lights button, you'll see an information display called Lights in Scene.

Another interesting part of LightWave when it comes to lighting is the Global Illumination option. This is an important area of your 3D lighting setup. However, you won't find Global Illumination settings in the Lights panel but in the Render Globals panel. We'll cover these settings just after the basic lighting information, later in this chapter.

NOTE

The Current Light drop-down list near the top of the Light Properties panel contains the name of each light in your scene. The default single distant light is named, simply, Light. Select this entry in the list and you can quickly rename it. You can do this for any light you add. Lighting in 3D animation is an art all its own.

Light Color

The color of the light you use is important and useful in your images and animations because it can help set tone, mood, and feeling. No light is ever purely white, and it's up to you to change LightWave's default pure-white light color. The color selector works the same as the other color selectors in LightWave. You can also animate the RGB values with the Graph Editor. In LightWave, you can even animate colored lights. Clicking the E button takes you to the Graph Editor, allowing you to vary the light color over time. Very cool! You'll use this for all kinds of things, such as animating a rock concert where you need to have fast-moving lights shining on the stage. By animating the light color, you can change the colors over time at any speed you want.

Light Intensity

When you start LightWave Layout or choose Clear Scene, by default there is always one light in your LightWave scene. It has a light intensity of 100% and is a distant light. Although you can use this one light and its preset intensity as your main source of light for images and animations, it's best to adjust the light intensity to more appropriately match the light and the scene at hand.

Did you know that light intensities can range from values in the negative to values in the thousands? You can set a light intensity to 9000% (or higher) if you want, just by typing in the value. The results might not be that desirable and may even be unstable, but you never know what your scene might call for. In general, if you want to create a bright, sunny day, you can use a point light, which emits light in all directions, with a light intensity of 150% or so for bright light everywhere. On the other hand, if you want to light an evening scene, perhaps on a city street, you can use spotlights with light intensities set to around 60%. As you build scenes throughout this book, you'll be asked to set up different light types, with varying intensities. This will also help you get a feel for setting the right intensity.

NOTE

The mini-slider (the left and right arrows) next to the Light Intensity setting in the Light Properties panel allows you to click and drag values ranging from 0 to 100. However, by manually entering values, you can set higher or even negative values!

Negative lights, or "dark lights," can also be handy depending on the scene you're working on. Whereas lights with a positive light intensity can brighten a scene, negative lights can darken a scene. You might be asking why you would darken a scene with a negative light instead of just turning the lights down. For example, you might have to add a lot of light to make areas appear properly lit. Depending on the surfaces you've set, the extra light might make one area look perfect while making other areas too bright. This is where negative lights come into play. Adding a negative light (any light with a negative light intensity value) takes away light from a specific area.